Reactions of Cobaltadichalcogenolenes with Diazo Compounds; Reactivities of Sulfur and Selenium in Formation and Dissociation of Alkylidene-Adducts

Abstract

Abstract Dichalcogenolatocobalt complexes CpCo(X1X2C2Ph2) (1: X1 = X2 = S; 2: X1 = X2 = Se; 3: X1 = S, X2 = Se) react with diazomethane or ethyl diazoacetate to yield 1:1 alkylidene-adducts CpCo[η3-(X1 , X2 , C)-{X1C(Ph)-C(Ph)X2CHR}] (4–9) with the evolution of N2. Thermal reaction of 9 (X1 = S, X2 = Se, R = CO2Et) causes isomerization to 8 (X1 = Se, X 2 = S, R = CO2Et). The reactivities and the regioselectivities of S and Se in the formation and dissociation of the alkylidene-adducts are discussed. 77Se NMR spectroscopy of the alkylidene-adducts was also studied.